<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .dropbtn {
            background-color: #4CAF50;
            color: white;
            padding: 16px;
            font-size: 16px;
            border: none;
            cursor: pointer;
        }

        .dropdown {
            position: relative;
            display: inline-block;
        }

        .dropdown-content {
            display: none;
            position: absolute;
            right: 0;
            background-color: #f9f9f9;
            min-width: 160px;
            box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
        }

        .dropdown-content a {
            color: black;
            padding: 12px 16px;
            text-decoration: none;
            display: block;
        }

        .dropdown-content a:hover {background-color: #f1f1f1}

        .dropdown:hover .dropdown-content {
            display: block;
        }

        .dropdown:hover .dropbtn {
            background-color: #3e8e41;
        }
    </style>
</head>
<body>
<h2>下拉内容的对齐方式</h2>
<p>left 和 right 属性指定了下拉内容是从左到右或从右到左。</p>

<div class="dropdown" style="float:left;">
    <button class="dropbtn">左</button>
    <div class="dropdown-content" style="left:0;">
        <a href="#">菜鸟教程 1</a>
        <a href="#">菜鸟教程 2</a>
        <a href="#">菜鸟教程 3</a>
    </div>
</div>

<div class="dropdown" style="float:right;">
    <button class="dropbtn">右</button>
    <div class="dropdown-content">
        <a href="#">菜鸟教程 1</a>
        <a href="#">菜鸟教程 2</a>
        <a href="#">菜鸟教程 3</a>
    </div>
</div>
</body>
</html>